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Trigger points – the keys to seasonal planning

Monday, January 28, 2019

Planning for 2019 should be front of mind for all producers. The 2018 season showed the extremes across SA with both drought and a bumper season occurring.
It is important to review your current business position given 2018. What are the critical decisions that need to be taken, particularly if the 2019
season is poor?

Whilst stocking rate is a key driver of profitability, it is important to ensure that it is managed to the season. The break to the season is a key factor
influencing carrying capacity. So determining trigger points (i.e. dates and strategies), can allow stocking rates to be optimised whatever the season.
It is particularly important to have a well-developed “exit” strategy for late or poor breaks to the season.

Carrying capacity should be manipulated relative to the season break. Table 1 provides an example of the impacts of time of the opening rains on carrying
capacity. Trigger points (i.e. critical dates) should be established for your own situation. The trigger points are dates at which actions must be
implemented.

Table 1: Impact of time of opening rains on livestock carrying capacity

Break of season (Date)

Potential Stocking Rate (DSE/winter grazed ha)

Planned Stocking Rate (DSE/winter grazed ha)

1 May

11

8

7 May

10

8

14 May

9

8

21 May

8

8

28 May

7

8

4 June

6

8

11 June

5

8

18 June

4

8

There are a range of tactics (see Table 2) that can be used to manage a late or poor break to the season that:

Maintain carrying capacity

Reduce feed demand

Table 2: Tactics to manage livestock with a late or poor break to the season

Recent years of failed springs have highlighted the importance of having trigger points also for the remainder of the season. A failed spring does not
happen over-night but slowly develops over weeks or even months. To ensure you are in a position to act early it is necessary to monitor rainfall and stored
soil moisture over winter and into spring. The use of moisture probes could be of great benefit. Monitor long term rainfall forecasts (www.bom.gov.au/climate/outlooks/#/rainfall/summary)
as these are generally more accurate in late winter and early spring (Table 3).

In seasons where winter rainfall is below average, stored soil moisture coming into spring will be low and pastures may struggle to grow rapidly as temperatures
begin to increase. Table 3 provides an example of the impact of dry winter/spring on livestock carrying capacity. Trigger points should be established
for your own situation/district.

Table 3: Impact of dry winter/spring on livestock carrying capacity

Date

Climate outlook Chance of above median

Potential Stocking Rate (DSE/winter grazed ha)

Planned Stocking Rate (DSE/winter grazed ha)

1 Aug

< 40% Aug-Oct

11

8

7 Aug

< 40% Aug-Oct

10

8

14 Aug

< 40% Aug-Oct

9

8

21 Aug

< 40% Aug-Oct

8

8

28 Aug

< 40% Sept

7

8

4 Sept

6

8

11 Sept

5

8

18 Sept

4

8

Tactics for these seasons may include:

Bringing forward the sale of sheep - such as cast-for-age ewes or surplus young sheep

Establishing a containment area to preserve the soil-pasture resource

Early weaning - lambs can be weaned at 8 to 10 weeks of age with access to high quality feed